The present invention relates to an apparatus for transmitting rotation about and translation along a first axis to a second axis and more specifically an apparatus for rotating a rotary driven tool with a driver oriented along an axis different from that of the rotating tool spindle and for transmitting translation for release of the toolholder within the spindle of a rotary driven tool.
A lathe is a machine tool for shaping an article of metal by holding and turning the article rapidly against the edge of a cutting tool. Typically, lathes used in a production environment contain a large number of cutting tools with each tool at a specific station on the lathe and capable of being indexed to a location to perform a cutting operation. In the past these cutting tools have been static while the workpiece rotates about the tool. Recent advances in machine tool technology have made it possible for the cutting tool to move relative to the workpiece is desired. A cutting tool mounted to a lathe and simultaneously capable of rotation is known in the art as a driven or motivated tool.
As an example of such a device, FIG. 1 illustrates a driven tool 10 mounted to a turret lathe disc 20 which may rotate about a turret lathe disc axis 22. The driven tool 10 is generally comprised of a cutting element 25, in this case a drill bit, secured to a toolholder 27 within a spindle 30 which is secured within a driven tool housing 35. The spindle rotates about a spindle axis 32. The driven tool housing 35 is secured to the turret lathe disc 20, however, generally the spindle 30 extends through a turret lathe disc receiving hole 40 which is one of many receiving holes about the circumference of the disc 20. A driver 45 along a driver axis 50 may be advanced to the turret lathe disc receiving hole 40 to engage the spindle 30 thereby causing rotation of the toolholder 27 and cutting element 25.
While the driven tool housing 35 remains attached to the disc 20, it is possible to rotate the disc 20 about the turret lathe disc axis 22 so that the receiving hole 40 is aligned with a pusher 60 along a pusher axis 65. Typically, a toolholder 27 is mounted within a spindle 30 in a releasable manner such that the toolholder 27 may be quickly released or secured. Such an arrangement may involve a translational motion directed to the spindle 30. It can then be seen that if the turret lathe disc 20 were rotated such that the driven tool housing 35 and the associated receiving hole 40 were aligned with the pusher axis 65, then the pusher 60 could be advanced to release the toolholder 27 so that a different toolholder could be inserted into the spindle 30. While FIG. 1 shows only a single housing 35 associated with a single receiving hole 40, the turret lathe disc 20 may have a plurality of housings such that each receiving hole 40 could be occupied by a spindle 30 of an associated housing 35.
Two such examples of a driven tool in which the driver and the pusher are coaxial to the spindle axis are found in U.S. Pat. No. 4,758,122 by Kubo issued Jul. 19, 1988 entitled "Tool Clamping Apparatus" and European Patent Application Number 90850031.7, Publication Number 0383735 A2 published Aug. 22, 1990 entitled "Tool Clamping Device."
FIG. 2 shows an arrangement in which the spindle 130 within the housing 135 of the driven tool 110 is along an axis 32 which is not parallel to the driver axis 50 or the pusher axis 65. Through a gearing arrangement such as two beveled gears at 90 degrees to one another, it may be possible to transmit the rotation of the driver 45 to the spindle 130. However when the driven tool housing 135 is indexed such that the turret lathe disc receiving hole 40 is aligned with the pusher axis 65, the manner in which the pusher 60 releases the toolholder 27 is not obvious. It should be noted that a single disc receiving hole 40 is typically the only access to the driven tool housing 35 available for both driving the tool and for releasing the toolholder 27.
Driven tool arrangements in which the axis of the driver are different from that of the spindle axis may be found in German Patent DE 3635910 A1 published Jun. 04, 1987 and German Patent DE 8616485-U1 published Dec. 18, 1986; however, these designs utilize gearing arrangements to drive the spindle and to release the toolholder from the spindle and as a result involve coupled gearing interaction. Furthermore, the toolholder is released through gearing utilizing a rotational motion.
It is an object of this invention to provide an apparatus of a fairly simple design that may be utilized to provide off-axis rotation and translation to a driven tool from along a single axis.
It is a further object of this invention to provide an apparatus for transmitting rotation and translation to an off-axis spindle through the single receiving hole associated with the driven tool mounted on a turret lathe disc.